Suction stabilized epicardial ablation devices

ABSTRACT

A suction assisted ablation device having a support surface, suction elements disposed adjacent the support surface, at least one electrode and at least one suction conduit is provided. The device may further include fluid openings, which allow fluid to irrigate target tissue and aid in ablation. A method for ablating tissue using suction is also provided.

This patent application is a continuation of U.S. patent applicationSer. No. 09/558,976, filed Apr. 27, 2000, now U.S. Pat. No. 6,514,250,the entire contents of which is specifically incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to ablation devices that are used to createlesions in tissue. More particularly, this invention relates to ablationdevices that use vacuum or suction force to hold the tissue in a mannerthat creates linear lesions.

BACKGROUND OF THE INVENTION

The action of the heart is known to depend on electrical signals withinthe heart tissue. Occasionally, these electrical signals do not functionproperly. Ablation of cardiac conduction pathways in the region oftissue where the signals are malfunctioning has been found to eliminatesuch faulty signals. Ablation is also used therapeutically with otherorgan tissue, such as the liver, prostate and uterus. Ablation may alsobe used in treatment of disorders such as tumors, cancers or undesirablegrowth.

Currently, electrophysiology (EP) ablation devices generally have one ormore electrodes at their tips. These devices may be used for bothdiagnosis and therapy. In one instance, electrodes at the tips of EPablation devices allow the physician to measure electrical signals alongthe surface of the heart. This is called mapping. When necessary, inanother instance, the physician can also ablate certain tissues using,typically, radio frequency (RF) energy conducted to one or more ablationelectrodes.

Sometimes ablation is necessary only at discrete positions along thetissue, is the case, for example, when ablating accessory pathways, suchas in Wolff-Parkinson-White syndrome or AV nodal reentrant tachycardias.At other times, however, ablation is desired along a line, called linearablation. This is the case for atrial fibrillation, where the aim is toreduce the total mass of electrically connected atrial tissue below athreshold believed to be critical for sustaining multiple reentrywavelets. Linear lesions are created between electrically non-conductiveanatomic landmarks to reduce the contiguous atrial mass.

Linear ablation is currently accomplished in one of several ways. Oneway is to position the tip portion of the ablation device so that anablation electrode is located at one end of the target site. Then energyis applied to the electrode to ablate the tissue adjacent to theelectrode. The tip portion of the electrode is then slid along thetissue to a new position and then the ablation process is repeated. Thisis sometimes referred to as the burn-drag-burn technique. This techniqueis time-consuming (which is not good for the patient) and requiresmultiple accurate placements of the electrode (which may be difficultfor the physician). Furthermore, even if the ablation process creates acontinuously linear line along the top surface of the target tissue, itis not assured that the tissue is continuously and completely ablatedthrough further layers of the target tissue (i.e. it is not assured thattransmurality is achieved.)

A second way of accomplishing linear ablation is to use an ablationdevice having a series of spaced-apart band or coil electrodes which,after the electrode portion of the ablation device has been properlypositioned, are energized simultaneously or one at a time to create thedesired lesion. If the electrodes are close enough together the lesionsrun together sufficiently to create a continuous linear lesion. Whilethis technique eliminates some of the problems associated with theburn-drag-burn technique, some repositioning of the ablation device maybe required to create an adequately long lesion. In addition, it may bedifficult to obtain adequate tissue contact pressure for each electrodein a multi-electrode ablation device. Also, the use of multipleelectrodes to create the linear lesion tends to make the tip portionmore expensive to make, more bulky and may cause the tip portion to bestiffer than with a single electrodes.

Another ablation-related problem results from the delivery of RF energyto muscular tissue, such as the heart. Ablation of such tissue usingconventional ablation devices has a tendency to char or burn the bloodor tissue with which the electrodes are in contact if the temperaturesexceed a certain threshold (for example, greater than 50° C.). Thisincreases the difficulty of the ablation process because it is necessaryto clean the tip portion after a series of burns. Moreover, overheatingthe blood in the vicinity of the target site can desiccate the blood andcan cause overburning.

It would be desirable to have an ablation device which is easy toposition in relation to the target tissue and which stays stable inposition in relation to the target tissue.

It would further be desirable to have an ablation device which, whenpositioned, is capable of easily creating a linear, transmural lesion.

It would further be desirable to have an ablation device that is able tomonitor tissue temperature in order to avoid burning the tissue.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a suction assisted ablationdevice. The device includes a support surface, having a first and asecond face, a plurality of suction elements disposed adjacent thesupport surface on the first face, at least one conductive elementdisposed adjacent the support surface on the first face, and at leastone suction conduit operatively connected with the suction elements. Thedevice may also include a maneuvering apparatus, such as a pull wireassembly. The device may also include at least one thermocouple element.The device may include one conductive element on a first support surfaceand a separate conductive element on a second support surface. Theconductive element may be a plurality of needle electrodes. The devicemay also include at least one fluid opening, which may be located withinthe conductive element. The conductive element may also be made of amaterial capable of releasing fluid.

Another aspect of the invention provides a method of ablating tissue. Asuction assisted ablation device comprising a support surface, having afirst and a second face, a plurality of suction elements disposedadjacent the support surface on the first face, and at least oneconductive element disposed adjacent the support surface on the firstface is provided. The first face of the device is placed adjacent anarea of tissue. Suction is conducted to the suction elements via thesuction conduit. The tissue is grasped with the suction and ablated. Atleast one fluid outlet may be provided adjacent the support surface andfluid may be released via the fluid outlet. The fluid outlet may belocated within the conductive element. The device may be placed using amaneuvering apparatus. At least one thermocouple element may be placedin communication with at least one suction element and a thermalenvironment of the suction element may be measured using thethermocouple element. The tissue may be ablated until the measurement ofthe thermal environment reaches a given level. A second support surfacehaving a second conductive element disposed adjacent a first face of thesecond support surface may also be provided. The first face of thesecond support surface may be placed in line with the first supportsurface to complete a circuit. The tissue is ablated.

Another aspect of the invention provides a tissue ablation system. Thesystem comprises at least two support surfaces, each support surfacehaving a first and a second face, a plurality of suction elementsdisposed adjacent the support surface on the first face, at least oneconductive element disposed adjacent the support surface on the firstface, at least one suction conduit operatively connected with thesuction elements, and at least one maneuvering apparatus, such as a pullwire assembly. The support surfaces may be disposed consecutively toeach other in a linear manner along the maneuvering apparatus so that acontinuous ablation lesion is achieved. The system may also include afluid delivery system, which may incorporate at least one fluid openingdisposed adjacent the support surface, a fluid conduit, a conductiveelement including fluid openings or a conductive element made of amaterial that releases fluid.

Another aspect of the invention provides a method of mapping the heart.A suction assisted ablation device comprising a support surface, havinga first and a second face, a plurality of suction elements disposedadjacent the support surface on the first face, at least one electrodedisposed adjacent the support surface on the first face and at least onesuction conduit operatively connected with the suction elements isprovided. The first face of the device is placed adjacent an area oftissue. Suction is conducted to the suction elements via the suctionconduit. The tissue is grasped with the suction. A signal is sentthrough a first electrode. The signal is received through a secondelectrode. The distance is mapped based on the signal from the firstelectrode to the second electrode.

Another aspect of the invention provides a method of pacing a heart. Asuction assisted ablation device comprising a support surface, having afirst and a second face, a plurality of suction elements disposedadjacent the support surface on the first face, at least one electrodedisposed adjacent the support surface on the first face and at least onesuction conduit operatively connected with the suction elements. Thefirst face of the device is placed adjacent an area of tissue. Suctionis conducted to the suction elements via the suction conduit. The tissueis grasped with the suction. Electrical impulses are sent through theelectrode at regular interval and the heart is paced to beat with theimpulses.

Another aspect of the invention provides a method of ablating tissue. Asuction assisted ablation device comprising a support surface, having afirst and a second face, a plurality of suction elements disposedadjacent the support surface on the first face, at least one needleelectrode disposed adjacent the support surface on the first face and atleast one suction conduit operatively connected with the suctionelements. The first face of the device is placed adjacent an area oftissue. The tissue is penetrated with the needle electrode. Suction isconducted to the suction elements via the suction conduit. The tissue isgrasped with the suction; and ablated.

The foregoing, and other, features and advantages of the invention willbecome further apparent from the following detailed description of thepresently preferred embodiments, read in conjunction with theaccompanying drawings. The detailed description and drawings are merelyillustrative of the invention rather than limiting, the scope of theinvention being defined by the appended claims in equivalence thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the suction assisted ablation device inaccordance with the present invention shown within a system for ablatingtissue;

FIG. 2 is a bottom view of one embodiment of the suction assistedablation device of the present invention, showing a first configurationof the suction elements and of the ablation electrodes;

FIG. 3 is a cross-sectional view of one embodiment of the suctionassisted ablation device of the present invention, showing suctionactivity and ablation pattern at one suction site;

FIG. 4 is a bottom view of a second embodiment of the suction assistedablation device of the present invention, showing a second configurationof the suction elements and of the ablation electrodes; and

FIG. 5 is a bottom view of another embodiment of the suction assistedablation device of the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows one embodiment of system 10 for ablating tissue, such asorganic tissue, in accordance with the present invention. Typically thetissue to be ablated will be located within the body cavity, such as theendocardial or epicardial tissue of the heart. Other body organ tissue,such as the liver, lungs or kidney, may also be ablated using thepresent invention. Tissue types that may be ablated include skin, muscleor even cancerous tissue or abnormal tissue growth.

System 10 may include an ablation device 12 that comprises at least oneconductive element 22, such as an electrode, and a connection 28 to apower source 30. Ablation device 12 may also include one or more suctionelements 44 and a suction conduit 34 that provides suction from asuction source 20. System 10 also may include a conduit 26 to anirrigation source 40 that provides irrigation fluid to the ablationsite. System 10 may also include temperature-sensitive elements 36,which may have the same power source 30 as the electrodes or may havetheir own power source.

System 10 may also include an indifferent (non-ablating) electrode 23which may serve as a return plate for energy transmitted throughelectrode 22. Electrode 23 may be placed elsewhere on the patient's bodyother than the ablation site. For example, electrode 23 may be placed onthe patient's back, thigh or shoulder.

Ablation device 12 may be any suitable ablation tool such as, forexample, a catheter, an electrocautery device, an electrosurgicaldevice, a suction-assisted ablation tool, an ablation pod, an ablationpaddle, an ablation hemostat or an ablation wire. Ablation device 12 andits components are preferably made of a biocompatible material such asstainless steel, biocompatible epoxy or biocompatible plastic.Preferably, a biocompatible material prompts little allergenic responsefrom the patient's body and is resistant to corrosion from being placedwithin the patient's body. Furthermore, the biocompatible materialpreferably does not cause any additional stress to the patient's body,for example, it does not scrape detrimentally against any elementswithin the surgical cavity. Alternatively, the biocompatibility of amaterial may be enhanced by coating the material with a biocompatiblecoating.

Preferably, ablation device 12 may be permanently or removably attachedto a maneuvering apparatus for manipulating device 12 onto a tissuesurface. For example, ablation device 12 may be attached to a handle 72such as shown in FIG. 1. Ablation device 12 may also be located on oneor more of the jaws of a hemostat-like device. Ablation device 12 mayalso be used in conjunction with a traditional catheter, for example, ina closed heart ablation procedure. Ablation device 12 may also bemaneuvered with a leash or pull-wire assembly. Ablation device may alsobe positioned on a pen-like maneuvering apparatus such as the Sprinklerpen available from Medtronic, Inc. Alternatively any appropriateflexible, malleable or rigid handle could be used as a maneuveringapparatus. Alternatively, any appropriate endoscopic orthoroscopic-maneuvering apparatus may also be used with device 12.

Device 12 also preferably includes a connection 28 suitable forconducting energy to device 12, particularly to conductive element 22from a power source.

The conductive element 22 of ablation device 12 may preferably be anelectrode. This electrode 22 may be positioned in any suitable place ondevice 12. Preferably electrode 22 is placed near an end of the device12, away from the user, to be more easily manipulated against the tissue60 to be ablated.

FIG. 2 shows one embodiment of a device 12 for ablating organic tissuein accordance with system 10 of the present invention. Suction assistedablation device 12 may comprise at least one face 15 that may conform tothe surface of the target tissue 60. The face 15 may be anyconfiguration that conforms to the surface of the target tissue, such asthe slightly curved or arcuate configuration of FIG. 1. Suction device12 may also include a suction conduit 34 that may be connected to leastone suction port 44 containing a suction opening 54 Suction device mayalso have at least one conductive element 22 disposed adjacent face 15.For example, two conductive elements 22, 42 are shown in FIG. 2.Preferably, the conductive element 22, 42 may be an electrode.Alternatively, suction device 12 may be made of a conductive polymer andmay serve as a conductive element. The distal end of device 12 may bepositioned near the ablation site and the proximal end may be positionedtowards the surgeon.

Preferably, when face 15 of suction device 12 is positioned against thetarget tissue, face 15 is adapted to conform to the surface of thetissue. This may be accomplished by making suction device 12 from aflexible material, such as, for example, a pliable polymer,biocompatible rubber thermoplastic elastomer or PVC. Alternatively,suction device 12 may be made of a more rigid material covered with anelastic over face 15. Suction force being applied through device 12 maycause device 12 to conform more closely to the shape of the targettissue. Device 12 may also be made of a malleable stainless steel orother material that is shapeable but not necessary flexible. Device 12may also be made of a conductive polymer.

Ablation device 12 may also be permanently or removably attached to asuction tube 24. Suction conduit 34 may be located within Tube 24.Conduit 34 may communicate suction to the target tissue surface via thesuction openings 54 of suction ports 44 in device 12.

The suction ports 44 may be arranged three to six ports in a row,although the specific number of ports and their position may vary.Preferably, for a linear lesion to result from the ablation process, theports are arranged linearly. Device 12 may be covered with a coveringduring insertion to prevent blood or tissue from clogging the ports 44,although this is not necessary. Such coverings may include coverings ofbiocompatible material that would cover device 12. Alternatively,coverings may be placed over ports 44, such as, for example, meshcoverings or ribbed coverings.

Each suction port 44 has a suction opening 54, which may be located inthe center or at a position slightly off-center of suction port 44.Although the openings 54 are circular in FIG. 2, other shapes may beused The suction ports 44 may also be any suitable shape. For example,in the embodiment of FIG. 2, the ports 44 are rectangular. Additionally,suction openings 54 may be covered with a covering such as describedabove to prevent blood or tissue from clogging the openings 54.

Preferably, each suction opening 54 has a smaller diameter than the areaof suction port 44. This creates a high resistance pathway betweensuction port 44 and suction conduit 34. Because of this, loss of atissue-to-port seal in one suction port (and thus loss of fixation ofthe suction port to the tissue) should not cause a precipitous pressuredrop in the remainder of the suction ports.

Ablation device 12 may be permanently or removably attached to at leastone connection 28 for conveying energy to electrodes 22, 42 from powersource 30. This energy is typically electrical, such as radiofrequency(RF) energy. However, it may also be any appropriate type of energy suchas, for example, microwave or ultrasound energy. Preferably, electrode22 runs the length of one side of device 12 and electrode 42 runs thelength of the opposite side of device 12. Electrode 22 may be maneuveredinto contact with the target tissue to ablate the tissue. In theembodiment of FIG. 2, two electrodes are shown in a bipolar arrangement.In such a bipolar arrangement, electrode 42 may also be maneuvered intocontact with target tissue 60 to ablate the tissue.

Ablation device 12 may be permanently or removably attached to at leastone fluid conduit 26 for irrigating the ablation site with a fluid.Alternatively, ablation site may not be irrigated. Fluid is conveyed tothe site via fluid openings 46 which are preferably integrated intoelectrodes 22, 42. However, fluid may be delivered to the site via aseparate irrigation mechanism, such as an irrigation pump (not shown).Moreover, fluid openings 46 may be disposed in any appropriate manner ondevice 12.

Suction ablation device 12 may be colored so that it can be easilyvisible against the target tissue. Alternatively, it may be clear toprovide less distraction to the surgeon or to provide viewing of bloodor other material being suctioned. Suction tube 24 may be a flexibletube constructed of a soft plastic which could be clear or colored.Suction ports 44 may be constructed of biocompatible rubber or epoxy,which could be clear or colored.

Electrodes 22, 42 may be constructed of stainless steel, platinum, otheralloys, or a conductive polymer. If device 12 is made of a more flexiblematerial, electrodes 22, 42 may be made of materials that would flexwith the device 12. Such flexible electrodes may be, for example, madein a coil or spring configuration. Flexible electrodes 22, 42 may alsobe made from a gel, such as a hydrogel. Furthermore, electrodes 22, 42may also be an electrode designed to deliver fluid, such as, forexample, a microporous electrode, a “weeping” electrode, or an electrodemade of a hydrogel.

A source 20 for creating suction may be attached to suction tube 24 atthe proximal end, preferably by a standard connector. This suctionsource 20 may be the standard suction available in the operating roomand may be coupled to the device 12 with a buffer flask (not shown).Suction is provided at a negative pressure of between 200-600 mm Hg with400 mm Hg preferred.

System 10 may include at least one temperature-sensitive element 36. Thetemperature-sensitive element 36 is positioned to communicate with atleast one of suction ports 44. Preferably, an element 36 is positionedto communicate with each suction port 44. These elements may be, forexample, thermocouple wires, thermisters or thermochromatic inks. Thesethermocouple elements allow temperature to be measured. Such monitoringof temperature may crucial. Too high a temperature will char the tissueor cause the blood at the ablation site to coagulate. Preferably, theelements 36 may be adhered within suction ports 44 so as to contact thetissue when it is suctioned into the ports. Thermocouple elements thatmay be used are 30 gauge type T thermocouple wire from Dodge PhelpsCompany. One type of conductive epoxy which may be used to adhere theelements is epoxy no. BA-2902, available from Trecon.

A separate temperature sensitive element 36 may be adhered or mountedwithin each suction port 44. Alternatively, a temperature sensitiveelement may be incorporated to run through all of the suctions ports 44.

As ablation occurs, it is sometimes desirable to irrigate the ablationsite with irrigation fluid, which may be, for example, any suitablefluid such as saline, an ionic fluid that is conductive or anotherconductive fluid. The irrigating fluid may cool the electrode 22 ofablation device 12. Irrigated ablation is also known to create deeperlesions that are more likely to be transmural. Transmurality is achievedwhen the full thickness of the target tissue is ablated. The applicationof fluid to an ablation site may also prevent electrodes, particularlymetal electrodes, from contacting the target tissue. Direct contact ofelectrodes to the target tissue may char or burn the tissue, which mayclog the device. Furthermore, continuous fluid flow may keep theablation device surface temperature below the threshold for bloodcoagulation, which may also clog the device Use of irrigating fluid maytherefore reduce the need to remove a clogged ablation device forcleaning or replacement. The presence of an ionic fluid layer betweenelectrode 22 and the tissue to be ablated may also ensure that an ionicfluid layer conforming to the tissue contours is created. In onepreferred embodiment, saline solution is used. Alternatively, otherenergy-conducting liquids, such as Ringer's solution, ionic contrast, oreven blood, may be used. Diagnostic or therapeutic agents, such asLidocaine, CA⁺⁺ blockers, or gene therapy agents may also be deliveredbefore, with or after the delivery of the irrigating fluid. Irrigationsource 40 may be any suitable source of irrigation fluid such as, forexample, a standard irrigation pump (not shown). This pump may also beconnected to power source 30 or may have its own source of power.Preferably, device 12 also includes a conduit 26 for deliveringirrigation to the ablation site from irrigation source 40.

In the embodiment of FIG. 1, fluid openings 46 may be located within theelectrode 22 itself. These openings may be holes machined into theelectrode 22. These openings may deliver fluid to the ablation site asdescribed above. Furthermore, electrode 22 may also be an electrodedesigned to deliver fluid, such as, for example, a microporouselectrode, a “weeping” electrode, an electrode made of a microporouspolymer or an electrode made of a hydrogel.

Referring now to FIG. 3, a close-up cross section is shown, taken alongline A—A of FIG. 1. In use, the embodiment of device 12 shown in FIGS. 1and 2 is placed against target tissue 360 so that when a suction forceis applied through openings 354, the target tissue is pulled into thesuction port 344. Fluid flows from openings 46 towards the target tissueas indicated by the arrows. Openings 46 are preferably angled at about30 degrees. Openings 46 preferably face towards suction ports 344.Ablation may begin at point 300 of the tissue and spread in thedirection indicated by the dotted arrows. If left over time, the entirepiece of tissue suctioned into the ports 344 may be ablated.

Electrodes 322, 342 are brought to a temperature sufficient to ablatethe tissue within the ports 44. Thermocouple elements 336 may be used tomonitor the temperature and when a given threshold temperature isreached, the surgeon may end ablation. This configuration of device 12is especially useful because it gives an accurate measurement of thetissue temperature since the tissue 360 is in direct contact with thethermocouple elements 336 located near ports 344. Thus the temperatureof the tissue may be measured by thermocouple elements rather than thetemperature of the electrode 322 being measured. The temperature of thetissue may also be determined based on ablation time.

The resulting lesion may be transmural. If the tissue is allowed to heatuntil the elements 336 indicate a temperature that usually indicatescell death (such as, for example, 15 seconds at 55°), this may indicatethat all the tissue has reached this temperature. In turn, this mayindicate that the lesion is transmural.

The ablation resulting from the arrangement of electrodes in FIGS. 2 and3 is linear. The width of the resulting ablation lesion may bedetermined by the space between electrodes 22, 42. The width of theresulting ablation lesion may also be determined by the depth of thesuction port 44 and the amount of the tissue suctioned into port 44 Thedepth of the lesion may be controlled by the depth of the suction port44 and the amount of suction force applied. The depth of the lesion mayalso be determined by the power applied to the conductive element andthe length of ablation time. The lesion resulting from the suction port344 of FIG. 3 will be repeated at each subsequent corresponding suctionport along the length of device 12. It is contemplated that for a longerlesion, a longer pod could be used or a series of pods could be strungtogether. A single pod could also be used to create a longer lesion byablating to create a first lesion and then being moved to create asecond lesion in line with the first lesion.

FIG. 4 shows another embodiment of the invention shown in FIG. 3. Inthis embodiment, electrodes 422, 423 are arranged in a unipolararrangement. Electrode 422 is placed on the device 12 while anotherelectrode 423 acts as a ground patch (indifferent, or non-ablatingelectrode) and is placed separately from the device 12. For example,electrode 422 on device 12 could be placed on a surface of the heart.Then corresponding electrode 423, which could be on a separate supportsurface, could be placed on the back of the patient to complete thecircuit. Although the suction ports 444 may be arranged in a linearmanner, ports 444 may be arranged in any other appropriateconfiguration, including for example, in an arcuate or radialarrangement. Although suction openings 454 may be circular, they mayalso be any appropriate shape to deliver suction. The lesions created bythis sort of unipolar arrangement tend to be wider than those created bya bipolar arrangement.

In the unipolar arrangement of FIG. 4, suction ports 444 are used tograsp target tissue (not shown) but do not pull the tissue into theports for ablating. Fluid would flow from openings in the electrode 423or in device 12 in the same manner as described above. Ablation wouldoccur in a similar manner to that described above although the device 12remains uniformly on the surface of the target tissue rather thanpulling the tissue into the ports for ablation.

It is contemplated that the electrodes used in the present inventioncould include any appropriate electrodes for performing ablation suchas, for example, metal electrodes, braided metal electrodes or needleelectrodes

FIG. 5 shows another embodiment of the suction ablation device 512 ofthe present invention, in which the conductive element may be a seriesof needle electrodes 522. A unipolar arrangement of the electrodes 522is shown. Alternatively, the electrodes may be arranged in a bipolarconfiguration similar to the arrangement of FIG. 2. In a bipolararrangement, one series of needle electrodes may be arranged down thelength of one side of the suction ports 544 and another series ofelectrodes 522 arranged down the length of the other side. Needleelectrodes may be used to poke through fatty tissue covering the targettissue. They may then be used to poke into the target tissue. Suctionmay then be applied as described above to hold electrodes in place.Ablation may then occur as described above. Additionally, device 512shows suction conduit 534 which may provide suction to ports 544 andpull wire 572 that serves as a maneuvering apparatus for device 512.

The device 12 may also be used in electrical mapping functions. Forexample, electrode 22 may be placed on one area of the heart and anappropriate signal sent through it. Then the electrode 42 may receivethe signal from electrode 22. From the strength of the signal, thedistance of electrode 22 from electrode 42 may be determined. Conductiondelay or block can help determine transmurality of lesions.

Device 12 may also be used in pacing functions. For example, device 12may grasp the heart as described above. Then energy may be sent throughelectrodes, 22, 42 at regular intervals. This energy may cause the heartto beat simultaneously to the signals sent through electrodes 22, 42.The device 12 may thus pace the heart at an appropriate beating rate,thereby serving as a pacemaker. This may be used, for example, during asurgical procedure when it might be necessary to regulate the heart'sbeating temporarily.

It should be appreciated that the embodiments described above are to beconsidered in all respects only illustrative and not restrictive. Thescope of the invention is indicated by the following claims rather thanby the foregoing description. All changes that come within the meaningand range of equivalents are to be embraced within their scope.

1. A suction assisted ablation device comprising: a support surface; atleast three suction ports disposed adjacent the support surface, each ofsaid at least three suction ports positioned adjacent the supportsurface in a substantially linear arrangement with respect to eachother; and a plurality of needle electrodes disposed adjacent thesupport surface and extending adjacent the suction ports, the pluralityof needle electrodes disposed such that a linear transmural lesion maybe formed in tissue by applying radio frequency energy to the tissue viathe plurality of electrodes.
 2. The device of claim 1 furthercomprising: a maneuvering apparatus operatively connected with thesupport surface.
 3. The device of claim 2 wherein the maneuveringapparatus comprises at least one pull wire.
 4. The device of claim 1further comprising: at least one thermocouple element adjacent thesuction elements.
 5. The device of claim 1 wherein the needle electrodesare arranged with a first series of the needle electrodes along a firstside of the suction ports and a second series of the electrodes arrangedalong a second side of the suction ports.
 6. The device of claim 1wherein at least some of the needle electrodes are centered between thesuction ports.
 7. The device of claim 1 further comprising: at least onefluid opening disposed adjacent the support surface.
 8. A suctionassisted ablation device comprising: a support surface; at least threeSuction ports disposed adjacent the support surface, each of said atleast three suction ports positioned adjacent the support surface in asubstantially linear arrangement with respect to each other; a pluralityof conductive elements disposed adjacent the support surface andextending adjacent the suction ports, at least a portion of theconductive elements having a fluid opening therein; the plurality ofconductive elements disposed such that a linear transmural lesion may beformed in tissue by applying radio frequency energy to the tissue viathe plurality of conductive elements.
 9. The device of claim 8 furthercomprising: a maneuvering apparatus operatively connected with thesupport surface.
 10. The device of claim 9 wherein the maneuveringapparatus comprises at least one pull wire.
 11. The device of claim 9further comprising: at least one thermocouple element adjacent thesuction elements.
 12. The device of claim 9 wherein the conductiveelements are arranged with a first portion of the conductive elementsalong a first side of the suction ports and a second portion of theconductive elements arranged along a second side of the suction ports.13. The device of claim 9 wherein at least some of the conductiveelements are centered between the suction ports.
 14. A method ofablating tissue comprising: providing a suction assisted ablation devicecomprising a support surface, a plurality of suction elements disposedadjacent the support surface, a plurality of needle electrodes disposedadjacent the support surface and at least one suction conduitoperatively connected with the suction elements; placing the deviceadjacent an area of tissue; penetrating the tissue with the needleelectrode; conducting suction to the suction elements via the suctionconduit; grasping the tissue with the suction; and applying radiofrequency energy to the tissue via the plurality of electrodes such thata linear transmural lesion is formed in the tissue grasped with thesuction.
 15. The method of claim 14 wherein the device is placed bymanipulating an apparatus operatively connected to the support surface.16. The method of claim 15 wherein the device is manipulated byactivating at least one pull wire.
 17. The method of claim 15 whereinthe device is manipulated by moving a handle.
 18. The method of claim 15wherein the device is manipulated by a catheter.
 19. The method of claim14 further comprising: stopping the ablation of the tissue when thetemperature monitored by a temperature sensing element adjacent thesuction element reaches a given level.
 20. A method of treating tissuecomprising: providing a suction assisted device comprising a supportsurface, a plurality of suction elements disposed adjacent the supportsurface, and a plurality of conductive element disposed adjacent thesupport surface, at least some of the conductive elements having a fluidopening; placing the support surface adjacent an area of tissue;conducting suction to the suction element; grasping the tissue with thesuction; penetrating the tissue with the conductive elements; releasingfluid via the fluid opening; and ablating the tissue.
 21. The method ofclaim 20 wherein the fluid is an energy-conducting fluid.
 22. The methodof claim 20 wherein the device is placed by manipulating an apparatusoperatively connected to the support surface.
 23. The method of claim 20wherein the device is manipulated by activating at least one pull wire.24. The method of claim 23 wherein the device is manipulated by moving ahandle.
 25. The method of claim 23 wherein the device is manipulated bya catheter.
 26. The method of claim 23 wherein the conductive element isa needle.
 27. The method of claim 20 further comprising monitoringtemperature with a temperature-sensitive element in communication withat least one suction element.
 28. The method of claim 27 furthercomprising discontinuing the ablation of tissue when the temperaturebeing monitored reaches a given level.